Michito Shiotsuka

Synthesis, X-ray molecular structure analysis, and study on ligand scrambling reactions of new thiolatogold(I) complexes with various phosphines

Abstract Treatment of Au(PPh3)Cl, (AuCl)2(trans-dpen) and (AuCl)2(dppfe) with Sn(SPh)(n-Bu)3 and/or PhSH/KOH affords Au(PPh3)(SPh) (1), (AuSPh)2(μ-trans-dpen) (2), (AuSPh)2(μ-dppfe) (3), (AuSPh)(μ-trans-dpen)(AuCl) (4), and (AuSPh)(μ-dppfe)(AuCl) (5) in good yields. All these thiophenolates are characterized by single crystal X-ray analysis, 1H and 31P NMR spectroscopy. 1 forms tetramer through Au⋯Au interaction and π–π interaction between the phenyl group in SPh and one of the phenyl groups in PPh3 in the solid state. An infinite chain structure is formed for 2 through intermolecular aurophilicity and these chains are connected by partial overlap (π–π interaction) of neighboring phenyl groups in SPh to give two-dimensional networks in the solid state. Similar infinite chains are formed through aurophilicity, but two-dimensional networks are not formed for 4 in the solid state. No multidimensional structure is formed for 3 and 5 in the solid state. 1H and 31P NMR spectroscopy of CDC13 solutions of 2, 3, 4, and 5 has revealed that rapid ligand scrambling takes place for 4 and 5.

Structure of Halogenophosphorincopper(I) Complexes in Solid State and Solution: Study with X-ray Crystallography and CP/MAS-31P{1H}-NMR Spectroscopy

Abstract Halogenophosphorincopper(I) complexes [Cu(dmppn)X] (X=Cl ( 1 ), Br ( 2 ), I ( 3 )) have been synthesized from 4,5-dimethyl-2-phenylphosphorin (dmppn) with copper(I) halide CuX (X=Cl, I) or copper(II) dihalide CuX 2 (X=Cl, Br). The crystal structure of 3 was determined by single crystal X-ray crystallography and showed supramolecular structure so called an infinite stair polymer. This complex is the only one for the infinite stair polymer of halogenocopper(I) complex with phosphorus ligand to the best of our knowledge. The chemical shifts for these complexes were observed to be 159.3( 1 ), 158.1( 2 ), and 151.2 ppm( 3 ) by CP/MAS– 31 P{ 1 H} NMR spectroscopy in the solid state and they showed significant upfield shifts over 20 ppm relative to that of the free ligand in CDCl 3 . These upfield shifts indicate that the phosphorin undergoes strong π-back donation from the copper(I) center and the magnitudes of the upfield shifts for the complexes showed an obvious increase in order of I>Br>Cl. This trend indicates that degree of the π-back donation is influenced by the donor character of the halogeno ligand through the copper–halogen bonding. The copper center in these complexes was further determined to have a four-coordination in a distorted tetrahedron with CP/MAS– 31 P{ 1 H}–NMR data and this result suggests that three complexes were formed the supramolecular structure of the infinite stair polymer in the solid state.

The syntheses of pyridine-functionalyzed methylidynetricobalt nona-carbonyl clusters, their X-ray analyses, and its coordination to Pd(II)

Abstract Two kinds of methylidynetricobalt nonacarbonyls with a pyridine functional group as an apical substituent have been synthesized from trichloromethylpyridine derivatives. The structures of two new clusters have been determined by single crystal X-ray analysis. EH-MO calculations have shown that the atomic charge on the N atom in NC5H4-3-CCo3(CO)9 is close to that of β-picoline. This cluster can coordinate to Pd(II) and trans-PdCl2{NC5H4-3-CCo3(CO)9}2 with a nanometer dimension has been synthesized as a precursor of molecular dot.

Synthesis of new multifunctional ligands containing S and N donor atoms and X-ray structure analyses on their Au(I) complexes

Abstract Two new multifunctional ligands containing S and N donor atoms have been synthesized. Their Au complexes have been synthesized and analyzed by single crystal X-ray method. New supramolecular structures have been created by partial π–π overlap among phenyl and/or pyridyl rings, but they have lacked in aurophilicity.

Photophysical Properties of Ruthenium(II) Polypyridyl-Gold(I) Ethynyl Dyads and Triads Containing Mono- or Diethynylphenanthroline Incorporated into Gold(I) Triphenylphosphine Organometallics

A new ruthenium(II)-gold(I) dyad, [Ru(bpy)(2){5-{(PPh(3))-Au-C[tripe bond]C}-phen}](PF(6))(2) (2), with a different substituted site compared to [Ru(bpy)(2){3-{(PPh(3))-Au-C[triple bond]C}-phen}](PF(6))(2) (1), and a triad, [Ru(bpy)(2){3,6-bis{(PPh(3))-Au-C[triple bond]C}-phen}](PF(6))(2) (3), with an unsymmetric diethynylphenanthroline relative to [Ru(bpy)(2){3,8-bis{(PPh(3))-Au-C[triple bond]C}-phen}](PF(6))(2) (4) have been prepared. These four ruthenium(II)-gold(I) compounds showed typical metal-to-ligand charge-transfer (MLCT) absorption bands in the 400-550 nm region and a lowest energy pi-pi* absorption involved with the gold(I) perturbation in the 300-400 nm region. Broad emission bands assignable to the triplet MLCT transition were definitely observed in all compounds, indicating that the hybrid architecture constructed with Ru(II)-polypyridyl and Au(I)-ethynyl units converts the blue-green gold(I) perturbed pi-pi* phosphorescence into an orange MLCT-based emission. The transient absorption difference spectra of four compounds showed the difference in the electron transfer process between 2 and other compounds 1, 3, and 4 under the excited state. Ru(II)-Au(I) compounds except for 2 receive the supposed charge injection from a ruthenium center to an extended pi-conjugated ethynyl-substituted phenanthroline, which contains one or two gold(I) organometallic unit(s), while 2 undergoes the electron transfer process from the ruthenium center not to the 5-ethynylphenanthroline but to one of the bipyridyl ligands under the excited state. This hypothesis is supported by the deflection of the spots of 2 and [Ru(bpy)(3)](PF(6))(2) from a linear correlation line in a plot of E(0-0) versus DeltaE(1/2), which was based on the electrochemical and emission data of Ru(II)-Au(I) compounds and mononuclear ruthenium(II) polypyridyl complexes.

Construction of molecular wires based on a gold(I) bis-σ-acetylide building block incorporated into ruthenium(II) polypyridyl complexes

An Ru(II)-Au(I)-Ru(II) triad has been synthesized from [Ru(bpy)2(3-ethynylphenanthroline)]2+ with Au(tht)Cl and characterized by spectroscopic means such as NMR and ESI-MS; the Ru(II)-Au(I)-Ru(II) triad shows an intense emission at 620 nm upon excitation at 360 nm, which suggests an efficient energy transfer from the Au site to Ru sites via extended pi-conjugation through the ethynyl units.